In Rosh Hashanah greetings, people wish to be inscribed in the Book of Life for the coming year.
The image comes from Jewish teachings about divine judgment on Rosh Hashanah, the Jewish New Year. Rabbinic tradition describes heavenly books being opened as God evaluates humanity. The names of the wholly righteous are written in the Book of Life, while other people’s judgment may remain unresolved until Yom Kippur, the Day of Atonement.
This idea explains the traditional greeting “L’shanah tovah tikatevu,” meaning “May you be inscribed for a good year.” A related greeting, “G’mar chatimah tovah,” asks for a favorable final sealing. The custom is not a reference to the Book of Exodus, which is a biblical book, or the Book of Jubilees, an ancient Jewish religious work.
The Book of Life also appears in Christian scripture, including Revelation, but the Rosh Hashanah greeting specifically reflects Jewish New Year and High Holy Day traditions.